Fluorescent lamps (also known as gas discharge lamps) economically illuminate an area. Due to the unique operating characteristics of fluorescent lamps, the lamps must be powered by a ballast. Electronic ballasts provide a very efficient method of powering fluorescent lamps and for adjusting the illumination level of fluorescent lamps.
Generally, an electronic ballast is driven by a single AC (alternating current) voltage supply having a particular phase. When power factor correction is required, the electronic ballast typically has a boost front-end for converting the AC voltage from an AC power source into a DC (direct current) voltage which has a value greater than the peak voltage of the AC power source. An inverter then converts the DC voltage into high frequency AC power.
It is highly desirable that dimming ballasts be capable of being powered from a multi-phase input. More specifically, it is desirable to have an electronic ballast that can be driven by two different AC voltages supplies supplying AC voltages at different phases.